The present invention relates to a recorder operating with drops of liquid for point-by-point recording of analog curves or alphanumeric characters and of images, in which nozzles are arranged in rows for producing the individual points. The nozzles have in front of inlet openings, contacted piezoelectric transducers arranged in such a way that as a result of electrical potential variations at the contacts, ink is expelled from the nozzle and applied to recording means located in front of the exit opening of the nozzles.
A recorder of the preceding species is known from U.S. Pat. No. 3,211,088. This patent document also describes how the distance between the nozzles arranged in one row can be varied in order to obtain greater recording intensity. It has been proposed that the intake areas of the exponentially-shaped nozzles be staggered. But even with staggered arrangement of the nozzle inlet openings, the space between the nozzles cannot be made smaller than the physical dimension of the individual piezoelectric transducers. When using individual block-shaped transducers or individual thick disk transducers, they must have a relatively large area in order to achieve sufficient deflections of the front surfaces of the transducers. This results in a relatively large distance of the individual nozzles from each other. Furthermore, the mounting of the individual oscillators becomes difficult, especially when narrow nozzle intervals must be maintained and the transducers are staggered.
It is, therefore, an object of the present invention to provide for a device of the initially described type through which sufficiently large drive movements for the ejection of ink can be achieved and which, nevertheless, provide the possiblity of very close spacing between the nozzles.
Another object of the present invention is to provide a device of the foregoing character which may be economically fabricated and maintained in service.
A further object of the present invention is to provide an arrangement which is simple in construction and has a substantially long operating life.